[Pepper] Wire up append mode writing support of FileIO

ppapi/proxy/file_io_resource.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ppapi/proxy/file_io_resource.h"
 
 #include "base/bind.h"
 #include "base/task_runner_util.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/c/pp_errors.h"
@@ skipping 380 matching lines @@
   called_close_ = true;
   if (check_quota_) {
     check_quota_ = false;
     file_system_resource_->AsPPB_FileSystem_API()->CloseQuotaFile(
         pp_resource());
   }
 
   if (file_handle_)
     file_handle_ = NULL;
 
-  // TODO(tzik): Post |max_written_offset_| and |append_mode_write_amount_|
-  // separately by using FileGrowth after the IPC signature changed.
   Post(BROWSER, PpapiHostMsg_FileIO_Close(
-      max_written_offset_ + append_mode_write_amount_));
+      FileGrowth(max_written_offset_, append_mode_write_amount_)));
 }
 
 int32_t FileIOResource::RequestOSFileHandle(
     PP_FileHandle* handle,
     scoped_refptr<TrackedCallback> callback) {
   int32_t rv = state_manager_.CheckOperationState(
       FileIOStateManager::OPERATION_EXCLUSIVE, true);
   if (rv != PP_OK)
     return rv;
 
@@ skipping 279 matching lines @@
   *output_handle = IPC::PlatformFileForTransitToPlatformFile(transit_file);
 
   // End this operation now, so the user's callback can execute another FileIO
   // operation, assuming there are no other pending operations.
   state_manager_.SetOperationFinished();
   callback->Run(result);
 }
 
 }  // namespace proxy
 }  // namespace ppapi